Typhoon Noru Bringing Wind and Rain to Northern Ryukyu Islands

Typhoon Noru was bringing gusty winds and heavy rain to the northern Ryukyu Islands on Friday.  At 5:00 p.m. EDT on Friday the center of Typhoon Noru was located at latitude 29.3°N and longitude 130.3°E which put it about 90 miles (140 km) south of Kagoshima, Japan.  Noru was moving toward the northwest at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 90 m.p.h. (140 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 959 mb.

The structure of Typhoon Noru has not changed much during the past 24 hours.  A large eye with a diameter of approximately 80 miles (130 km) occupies the center of the typhoon.  A broken eyewall surrounds the eye.  Strong thunderstorms surround the eastern side of the eye, while a broken ring of weaker showers and storms mark the western edge of the eye.  The strongest winds are occurring in the thunderstorms on the eastern edge of the eye.  Thunderstorms in the core of the circulation are generating upper level divergence which is pumping away mass in all directions.  A primary rainband extends from the eastern side of Typhoon Noru around the southern and western sides of the circulation.  Several other shorter bands are outside this primary rainband.  Typhoon Noru continues to exhibit a structure similar to an annular hurricane.

Although the core of Typhoon Noru is fairly large, the overall size of the storm is not as big as some typhoons.  Winds to typhoon force extend out about 40 miles in all directions from the center of circulation.  Winds to tropical storm force extend out about 160 miles (260 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Noru is 13.9.  The Hurricane Size Index (HSI) is 17.0 and the Hurricane Wind Intensity Size Index (HWISI) is 30.9.

Typhoon Noru will be in an environment favorable for intensification for about another 24 hours.  Noru will move over water where the Sea Surface Temperature is near 30°C.  An upper level ridge north of Noru is producing northerly winds which are blowing toward the top of the typhoon.  Those winds are fairly weak and there is not much vertical wind shear.  Typhoon Noru is likely to intensify during the next 24 hours and it could strengthen into the equivalent of a major hurricane again.  In a day or so, an upper level trough will approach from the west and wind shear will increase.  Typhoon Noru will weaken faster after it makes landfall in Kyushu.

Typhoon Noru is moving slowly around the western end of a subtropical ridge.  Noru is in an area where the steering currents are weak and the will remain weak for another 24 to 48 hours.  An upper level trough will approach Noru from the west in a day or so.  Southwesterly winds ahead of the trough will start to steer Typhoon Noru toward the northeast at a faster rate.  On its anticipated track Typhoon Noru could make landfall in Kyushu in less than 36 hours.

The large core and strength of Typhoon Noru make it capable of bringing strong winds and heavy rain to a large area.  Typhoon Noru will continue to bring wind and rain to the northern Ryukyu Islands for another 24 to 36 hours.  Noru could also cause wind damage, heavy rain and floods on Kyushu, Shikoku and western Honshu when it moves over those regions.